This invention relates to assembly techniques for storage systems. More particularly, the invention relates to a process for the assembly of disk drive parts on a disk drive chassis.
Disk based data storage devices for storing digital electronic information have been in use in the computer industry for several decades. The storage devices operate by storing digital information on magnetic disk media, which can be either rigid or flexible and are mounted on a rotating hub. These storage devices are commonly referred to as disk drives. Disk drives come in two varieties: removable media and fixed media drives.
Removable media drives accept the disk media in the form of a removable cartridge. When the cartridge is inserted into a disk drive, a spindle motor in the drive couples with the disk hub in order to rotate the disk within the cartridge at a given speed. In fixed media drives, by contrast, the disk hub is permanently attached to the spindle motor. Disk drives typically employ either a linear actuator mechanism or a rotary actuator mechanism. The actuator positions the read/write head(s) of the disk drive on the recording surface(s) of the disk.
The general technological trend is one of shrinking component sizes. This trend also applies to the disk drive industry. For example, 2" inch disk drives (and smaller) are becoming prevalent. Correspondingly, disk components and tolerances are shrinking as well. In such drives, the relative placement of components becomes a key technical issue. For example, to ensure proper operation of the disk drive, the actuator to spindle motor placement becomes critical. Particularly with removable media disk drives, if the dimensional relationship of the actuator and spindle motor is inconsistent among drives, the drive may fail to operate reliably.
Traditionally, disk drive components such as spindle motors and actuators were attached to the drive chassis by screwing components in place, using slip rings, or snap in features. However, where the coplanarity and dimensional relationship of the components is critical, the traditional method provide insufficient precision.
Traditional welding techniques of metal components use lap joints or butt joint of metallic components. However, where the dimensional tolerances are critical the lap joint and butt joint methods may be untenable. If lap joint methods were used in such critical applications, such as the assembly of disk drives, small variations in components tolerances, such as bends and burrs in the metal components that occurs during stamping, may be enough to cause tolerance problems in the finished disk drive. The dimensional tolerance problems would eventually prevent further technological advances due to the reduction of drive components and drive size. Moreover, to account for the component tolerance variations, the components themselves would have to meet extreme tolerances. As a result of the extreme component tolerances that would be necessary, the cost of components would ultimately drive up the drive cost.
The extreme component tolerances and higher drive costs could be circumvented by an improved assembly process. Thus there is a need for an improved economical assembly process of storage devices that improves dimensional relationships of components.